ES2226495T3 - METHOD FOR THE MANUFACTURE OF PRESSURE COMPOUND CONTAINERS AND PRODUCTS MANUFACTURED WITH THE METHOD. - Google Patents

Abstract

Process for the manufacture of a composite container comprising the following stages: A) pre-forming of a composite sheet structure (7) for the container, sheet structure manufactured at least in part from a thermoplastic material and having a thermoplastic sheet liner (1) sealing the inner surface thereof; B) in a mold (13), heat the composite sheet structure (7) and the thermoplastic sheet liner (1), while at least one force is applied, which tends to push the thermoplastic sheet liner and the composite sheet structure towards the Exterior; C) continue with step B) until the thermoplastic sheet liner and the composite sheet structure are consolidated and the outer surface of the composite sheet structure becomes fluid and flows to adapt to the inner surface of the mold, thereby forming a container compound; D) allow the formed composite container to cool; and E) remove the formed composite container from the mold.

Description

Method for the manufacture of containers pressure compounds and products manufactured with the method.

The present invention relates to the technique of manufacture of pressure vessels and, more particularly, to Improved methods for manufacturing composite pressure vessels, as well as to composite pressure vessels manufactured according to With the improved methods.

Traditionally, pressure vessels, such as water heaters, kettles, gas tanks to pressure and the like, have been manufactured from metals such as steel. However, in recent years, it has been winning in importance of using composite pressure vessels. These composite pressure vessels are usually manufactured by a filament winding process, which uses plastic resins thermosetting materials such as epoxy resins, polyesters and vinyl esters. In summary, this technology consists of processes of impregnating dry fibers, such as fiber cords of glass, with catalyzed resin, before applying to a mandrel. Pre-impregnated fibers can also be used ("prepreg"). The mandrel and the applied compound harden then, at room temperature or by applying heat, to constitute the laminate and get a hard resin and a laminar structure fibrous This laminar structure is removed from the mandrel or the same mandrel becomes part of the finished product. Although the Product specific application determines the exact function of the resin, in all cases serves as a support structure for keep the continuous fiber cords in position.

The thermosetting resins used in these processes can be considered as a type of low temperature product, which are characterized by their relative ease of use, low cost and availability. These resins have long served to meet the performance requirements of a wide range of products such as pressure vessels.

However, these resin systems present a well-known problem, such as their skills Limited thermal, unsatisfactory product aesthetics finished, short duration, lack of suitability for recycling and some aspects related to manufacturing, such as machine downtimes due to cleanliness and costs of material handling. In addition, there are some problems environmental, derived from the exposure of workers to steam, excessive fogging, emissions, etc. found during manufacturing processes Some thermosetting resins techniques improve performance due to higher thermal fitness, although associated with unacceptable material costs.

In addition, due to the materials and processes used, pressure composite containers, prepared according to state-of-the-art processes harbor internal tensions residual and important that, along with certain incompatibilities of the materials, sensitive to temperature, limit the ranges of pressure and temperature at which the containers are used to Pressure.

Document DE4215756A describes a process for produce hollow bodies, such as pressurized bottles, consisting of two layers. The first layer is obtained by extrusion, injection or blow molding of compressed air and the second layer is wrap around the first layer with a string of fibers thermoplastics The winding is heated above the point of fusion of the fibrous thermoplastic material so that the fibers thermoplastics are melted and consolidated in the second layer and then If heated, the container is placed in a mold.

Therefore, requests for better yields, environmental aspects, manufacturing and opportunities in the new markets have highlighted the limitations in the use of thermosetting resins for manufacture of composite pressure vessels. Are therefore highly desirable pressure composite containers that present greater possibilities, in terms of temperature and pressure, better appearance and durability, as well as characteristics of impact resistance and, as regards its manufacture, be more environmentally friendly, more profitable and present Less manufacturing problems.

Therefore, experts in the field recognize that a process for the manufacture of containers pressurized compounds, which achieves improvements in all these areas, It requires a fundamentally different philosophy. The present invention aims to offer such a process, fundamentally improved, as well as pressure vessels manufactured with said process, and by which the following are obtained features: improved contact, at elevated temperatures, between fiber and resin, better control of the relationship reinforcement / matrix, waste materials that can be recycled effectively, reduction of problems with regulations due at emissions, higher processing speeds for the rolled up (or other mode of coating) and in the stages of hardening, potential labor savings due to the less material handling, reduction of surface space, adaptability to automation, safer environment for employees, simplification of processing lines and material storage and handling, shorter times switching, faster commissioning, lower costs of training, reduction in energy costs, etc. By consequently, the pressure vessels manufactured according to the process they practically lack internal tensions and present a improved performance compared to the pressure vessels of the state of the art because, among other things, they can resist higher pressures and temperatures, are more impact resistant and also have a noticeably finished improved.

Therefore, one of the general objects of The present invention is to offer an improved process for the manufacture of a pressure composite vessel.

One of the objects of the present invention is, more particularly, to offer such an improved process that, contrary to what happened with the manufacturing processes of State-of-the-art composite pressure vessels, presents Advantages such as: better control of the reinforcement / matrix ratio, effective recycling of waste material, less number of problems with regulations due to emissions, speeds of higher processing for the winding stages (or alternatives to winding) and hardening, savings considerable labor due to the lower handling of the material, reduction of surface space, susceptibility automation, safer environment for employees, simplification of processing and storage lines and material handling, faster switching times, faster startups, lower training costs as well as lower energy costs, etc.

In sum, these and other objects of the invention are obtained through a process for manufacturing a container compound, which includes the following stages: A) pre-formed of a thermoplastic sheet structure for the container, (for example winding fiberglass, and a thermoplastic material on a thermoplastic mandrel) comprising a liner based on a thermoplastic sheet that seals the inner surface thereof; B) in a mold (which can be optionally heated), heat the composite laminar structure and thermoplastic laminar lining, while at least one force is applied (for example, evacuating the mold, pressurizing the thermoplastic laminar lining or both things) that tends to push the thermoplastic sheet liner and the composite laminar structure outwards; C) continue with the stage B) until the thermoplastic laminar liner and structure composite laminar are consolidated and the outer surface of the composite laminar structure becomes fluid and flows to adapt to the inner surface of the mold, thus forming a composite container; D) let the composite container cool formed; and E) remove the formed composite container from the mold. How suitable thermoplastic materials, the polyethylene, polypropylene, polybutylene terephthalate and polyethylene Terephthalate

The object of the invention is indicated. particularly and clearly claimed in the part of conclusion of the specification. However, the invention, both as far as organization and method of work is concerned, it can be better understand with reference to the following description, taken together with the claims and the attached figures, where:

Fig. 1 is an illustration of a liner / mandrel used to obtain the first embodiment of the invention;

Fig. 2 is a cross-sectional view of along lines 2-2 of fig. one.

Fig. 3 is an illustration of the lining / mandrel shown in figs. 1 and 2 that is coated with a layer of material based on intermingled thermoplastic fibers;

Fig. 4 is a view of the liner after having coated it with the layer of thermoplastic fibrous material intermingled and comprises a fragmentary sectional view extended cross section;

Figs. 5A, 5B and 5C are section views transverse, taken along lines 5-5 of fig. 3, which illustrate three variants of a first type of material, which can be rolled over the thermoplastic liner to proceed to coating;

Fig. 6 is a cross-sectional view, taken along lines 6-6 of fig. 3, illustrating a second type of material, a wick of any of the three variants illustrated in figs. 5A, 5B and 5C, which You can roll over the thermoplastic liner to get the covering;

Fig. 7 is a cross-sectional view, taken along lines 18-18 of fig. 3, illustrating a third type of material, a thread of the second type of material, which can be rolled over the thermoplastic liner to get the coating;

Fig. 8 is a transparent view of a mold, which shows the modified liner enclosed in a mold, in which it subject to heat and at least one force, which tends to push the modified lining inside the profile defined by the internal surface of the mold;

Fig. 9 is a cross-sectional view partial, enlarged, of the modified lining, which illustrates the effects of heat and force on it; Y

Fig. 10 is a view similar to fig. 8, which shows the modified liner enclosed in a different type of mold.

Fig. 11 is a cross-sectional view of an open mold, which contains a thermoplastic component preforming a pressure vessel manufactured according to a second embodiment of the invention.

Fig. 12 is a view similar to fig. 11, which illustrates a step in the second embodiment of the invention, in the which introduces a mass of fluid thermoplastic material in the inside the preformed component, as the second component of the pressure compound vessel to be formed;

Fig. 13 is a cross-sectional view, similar to figs. 11 and 12, although with the mold closed and the components of the pressure vessel subjected to a force that form the pressure vessel against the inner wall of the mold;

Fig. 14 is a cross-sectional view of an open mold, which contains a thermoplastic component preformed of a pressure vessel, manufactured according to a third embodiment of the invention and also a liner component thermoplastic, arranged inside the first component;

Fig. 15 is a cross-sectional view, similar to fig. 14, but with the mold closed and the components of the pressure vessel subjected to a force that forms the pressure vessel against the inner wall of the mold;

Fig. 16 is a cross-sectional view. of the finished pressure composite container, prepared according to process shown in figs. 14 and 15;

Fig. 17 is a cross-sectional view of an open mold, which contains a thermoplastic component preforming a pressure vessel manufactured according to a fourth embodiment of the invention and also a liner component exterior arranged outside the first component and a inner lining component disposed inside the first component;

Fig. 18 is a view similar to Figure 17, but with the mold closed and a force to produce components connected to the mold;

Fig. 19 is a view similar to fig. 18, which shows the pressure vessel that is forming in the mold under the influence of heat and one or more forces that push the components of the pressure vessel forcing them to adapt to the contours of the inner wall of the mold;

Fig. 20 is a cross-sectional view. of the finished pressure composite container, prepared according to process shown in figs. 17, 18 and 19;

Fig. 21 is a cross-sectional view of a mold containing a preformed thermoplastic component of a pressure vessel, already provided with a thermoplastic liner, the pressure vessel being manufactured according to the fifth embodiment of the invention

Fig. 22 is a view similar to fig. 21, which shows the pressure vessel to be formed in the mold under the influence of heat and one or more forces that push the components of the pressure vessel forcing them to adapt to contours of the inner wall of the mold; Y

Fig. 23 is a cross-sectional view. of the finished pressure composite container, prepared according to process shown in figs. 21 and 22; Y

Fig. 24 A is a cross-sectional view, illustrating a preliminary stage in the preparation of a container pressure compound according to a sixth embodiment of the invention.

With reference, first to figs. 1 and 2, it shows a thermoplastic liner / mandrel 1 for the manufacture of a pressure composite container according to a first embodiment of the invention. In the embodiment of the example, the liner / mandrel 1 is a preformed structure, generally elongated, ending, in each dome-shaped end 2, 3 having an axial opening, central 4, 5. The thermoplastic liner 1 can be for example of polypropylene, polyethylene, polybutylene terephthalate, polyethylene terephthalate or fiber (eg fiberglass) impregnated with polypropylene, polyethylene, polybutylene terephthalate or polyethylene terephthalate or any other thermoplastic material with suitable features and can be prepared by a process conventional suitable as the molding of a combination of fibers chopped, directional fiber, woven and / or knitted material, sewn or welded together in the profile of the container and intermingled with thermoplastic material.

As shown in fig. 3, it rolls up methodically on the outer surface of the thermoplastic liner 1 a filament, wick, thread or ribbon 6 of fiber, (for example fiber glass, carbon fiber, boron, etc.) and a material thermoplastic, to form a coating 7, practically uniform, as shown in the partial cross section enlarged from figure 4. This stage can be performed, for example, mounting the thermoplastic liner 1 on a mandrel 8 and making rotate the liner in the manner indicated by arrow 9 while leaving methodically feeding the filaments, the wick and the tape 6 from a transverse, lateral and reciprocal source, such as the represented by double arrow 10 and continuing with the procedure until the coating 7 has reached the thickness wanted. Material 6 can be rolled in "cold" over the thermoplastic liner 1 or can be passed through a heater 12 which, in some applications, results in a coating more uniform 7 (fig. 4), with better functional characteristics and / or aesthetic. The resulting structure 11 is still processed then in the manner described in detail in the following.

It has been proven that it is desirable to modify adequately feed rate in the regions of the domes and ends, in order to obtain a thickness virtually uniform coating over the entire length of the liner 1. In the state of the art, others are well known alternative winding techniques to achieve a coating satisfactorily uniform, for example the US Patent 3,282,757 entitled "METHOD FOR MANUFACTURING A CONTAINER PRESSURE REINFORCED WITH FILAMENT ", by Richard C. Brussee, who is incorporated herein by reference and describing several winding techniques, which can be used in the practice of present invention

However, the form and especially the type of fiber and thermoplastic material 6 have an importance significant in the implementation of the invention, so The emphasis is briefly on figs. 5A, 5B, 5C, 6A, 6B and 7, illustrating suitable variants of the material 6 that can be use in the implementation of the invention. In Figure 5A, separate cords of thermoplastic material 13A are wound and 12A fiber, together or separately but more or less contiguous, as indicated in 6A, on the liner / mandrel 1. The suitable types of thermoplastic material 13A that can be use in the implementation of the invention, for this purpose, they may be, without this implying any limitation: polyethylene, polypropylene, polybutylene terephthalate and polyethylene Terephthalate

Fig. 5B shows a cross section of a second variant 6B for material 6, where the fiber filament 12B is coated with thermoplastic material 13B, for example by double extrusion or by any other suitable preliminary process. Similarly, fig. 5C shows a cross section of a third variant 6B for material 6, where the fiber filament 12C is coated with a powder of thermoplastic material 13C.

However, before rolling over the lining / mandrel 1, fiber 12 and thermoplastic material 13 (in any of the shapes shown in figs. 5A, 5B, 5C) se mix first, preferably, to form a 6D wick, as shown in figure 6 A, or a 6E thread of these wicks, as shown in fig. 6B. Another preferred configuration for the material 6 is shown in fig. 7, in the form of 6F tape based on intermingled thermoplastic fiber and material. The wicks suitable, intermingled strands and straps of fiber, for example fiberglass and thermoplastic material, are found in the market, and a family of products, which has been proven can be suitably used in the present invention, it distributes under the brand name of Vetrotex Twintex®. Twintex prepares through a protected process, in which filaments of fiberglass (for example 17 microns in diameter) with filaments (eg 20 microns in diameter) thermoplastic (eg polyethylene or polypropylene) during the continuous production of wicks, threads and tapes that are available in this way, as well as in tissue shape.

Therefore, and by way of example only, the thermoplastic liner / mandrel 1 can be manufactured in turn with Twintex® fabric, which are sewn and welded together and subjected to a suitable heat treatment, for example in a mold to obtain the preform, which is subsequently wound with fiber and material  thermoplastic 6 to obtain the immediate structure 11.

With reference now to figure 8, once intermediate structure 11 has been prepared in the manner described or in any suitable way, it is placed in a mold 13 (two elements in the example). The mold is then heated, e.g. ex. by built-in resistance heaters, represented by the heater 15B, operated, so that they can be controlled, from an E 15A source and / or circulating hot oil, heated by a source H 14A, through coils 14B and / or any other conventional file suitable for heating molds In addition, at least one force is applied to the mold 13 and / or inside the intermediate structure 11, which tends to make the outer surface of the intermediate structure adapts to the internal surface 13A (fig. 9) of the mold when the heat applied Q makes thermoplastic liner 1 and rolled coating 7 they melt and flow in the direction of the mold. The forces can be generate by applying external compression to the mold halves, to force them to come together, as indicated by the arrows designated "F" and / or setting pressure inside the thermoplastic lining 1 using, e.g. e.g. gas under pressure from a suitable source 16, transported inside the liner 1 to through a duct 18. If pressure is used, the covers (threaded or permanent) 19 serve to seal the ends of the intermediate structure 11.

Heat is then suppressed in mold 13, allowing the pressure compound vessel to be just form hardens and can be removed by opening the mold in the form conventional.

In practice, two can be taken into account important optional considerations. First, it has verified that the mold must be ventilated, as shown with the openings distributed by the periphery 17, shown in the fig. 8, to allow the enclosed air to escape to the set the pressure vessel against the inner wall of the mold and therefore achieve a particularly fine finish of the outer surface of the pressure vessel, which requires very little subsequent surface finish, if required. In second place, in order to ensure a complete merger between the thermoplastic liner 1 and rolled coating 7, has been verified that it is preferable to select the materials corresponding with somewhat different melting temperatures for the lining and coating. More particularly, the best results are obtained if the heating speed is controlled and the melting point of the liner is chosen so that it is higher than the coating, so that the thermoplastic material melts around the fiber while the lining is softening, although does not melt completely during the fusion process. For example, as is well known, in the state of the art, the melting point Polypropylene ranges from 148 ° C (300 ° F) to 165 ° C (330 ° F), while that of polyethylene ranges between 48 ° C (120 ° F) and 60 ° C (140 ° F).

As shown in fig. 10, the container Pressure compound can be manufactured according to a similar process, in which uses a two-element mold 20, provided with some matching flanges 21, 22, which bolt together, defining fully therefore a predetermined three-dimensional shape for the inside surface of the assembled mold. In this configuration, the intermediate structure 11 is placed inside the assembled mold. Then, heat Q is applied, as described previously, while the interior of the structure is pressurized intermediate to form the pressure composite vessel. In this variant, it is not necessary to apply external compression forces to the mold. Preferably, openings 17 are arranged by the reasons stated above.

Figs. 11, 12 and 13 illustrate a process different, although related, for the manufacture of a container compound under pressure. For clarity, these figures are shown in cross section. With reference to fig. 11, one is placed preform 31 in a two-piece mold 30A, 30B. The preform 31, which it will serve as an outer layer for the pressure compound vessel that it is going to be manufactured, it can be prepared in the way described formerly for thermoplastic liner 1, although alternatively, it can be prepared in the manner described formerly for intermediate structure 11; that is, the lining thermoplastic 1 rolled with fiber coating 7 and a thermoplastic material

As shown in fig. 12, a mass 32 of molten thermoplastic material, such as polyethylene, polypropylene, polybutylene terephthalate and polyethylene terephthalate, it is extruded into elongated tube shape through an axial opening 37 in the upper end of the preform 31. The material of the dough 32 is choose to form a good union with a certain preform 31. An insert 33 is juxtaposed, which can be threaded or permanent, with respect to the axial opening 37 and within the mass 32. Similarly, if preform 31 comprises a second axial opening 38, another insert 34 is juxtaposed in the second opening

Those skilled in the art will clearly appreciate that melt 32 stores a large amount of latent heat. With reference now to fig. 13, the semi-molds 30A, 30B are closed, and the inside of the dough is subjected to pressure, from a source 35 of pressurized gas, through a conduit 36, so that the thermoplastic material 32A in the mass not only flows colliding with the inner surface of the preform 31A, but transmits sufficient heat to preform 31A To make it fluid. Therefore, the outer surface of the preform 31A flows to fit the inner surface of the mold, melting the inserts 33A, 34A with the rest of the structure or defining removable inserts, according to It is intended.

Yes, in a given configuration, it does not exist enough latent heat in the dough to achieve consolidation complete with the preform and thermoplastic material as well as the planned adaptation of the outer surface of the preform to the inner surface of the mold, heat can then be applied additional Q to the mold to carry out the formation of the container under pressure 37. The mold can then be allowed to cool (or it can be cool down in the conventional way) and open in a way that the finished pressure vessel can be removed.

Figs. 14, 15 and 16 (shown in section transverse) illustrate another molding process to form a preform 41 and turn it into a pressure vessel 41A. Doing reference, first, to fig. 14, preform 41 can be prepare according to any of the corresponding processes described  above, including the process described in relation to figs. 1-10, which consists of winding fibers and a thermoplastic material intermingled on a thermoplastic liner which may have been prepared, in turn, by welding or sewing together intermingled fiber and thermoplastic material components. Or, the preform 41 can be molded relatively enough, from a suitable thermoplastic material such as polyethylene, polypropylene, polybutylene terephthalate and polyethylene Terephthalate

The preform 41 which, in the example, has axial openings 44, 46, is inserted into a mold Two-piece 40A, 40B. Then, some pieces are juxtaposed threaded 43, 45 in openings 44, 46 (could be used alternatively, of course, inserts like 33, 34, used in the process illustrated in figs. 11-13 or any other type of insertion, depending on the precise configuration desired for the pressure vessel). Yes threaded inserts are used, their material will have to be choose so that it has a melting point much higher than the point of fusion of preform 41. At least one of the pieces inserted includes an opening to admit a bag of inflatable rubber-silicone 42 inside the preform 48. In addition, a heater 48 is disposed within the bag inflatable 42, which is chosen so that it has characteristics of thermal manipulation exceeding the melting point of the preform 41. A silicone rubber suitable for inflatable bag 42 is Mosites 1453D, supplied by Mosites Rubber in the United States and Aerovac Systems (Keighley) Ltd. in the United Kingdom.

The heater 48 can be of any type suitable, such as an electric resistance heater, performing the feeding by means of conductors (not shown), which extend through the opening in threaded insert 43 and dock to a suitable controllable power supply (not shown). In addition, it can be arranged, if deemed necessary or desirable, the preheating separated from the preform 41, by means of a set of heaters, represented by the heaters of electrical resistance 47A, 47B, near the walls of the preform The heaters 47A, 47B can be fed through conductors (not shown) that extend through one of the openings  axial 44, 46, or both, in preform 41 and which are coupled to a suitable controllable power supply (not shown). He mold 40A, 40B in turn, can be preheated conventionally and / or heated during the molding process.

If preform 41 has to be preheated (by in general, to increase the total yield of the process), this stage is done to make the preform almost fluid and the heaters 47A, 47B are removed from the mold 40A, 40B, which closes so. With reference now fig. 15, the rubber bag inflatable silicone 42 swells from a gas source 49 to pressure, through a duct 50, while heater 48 heats preform 41 until it reaches the fluid state, through of the bag, so that said bag exerts directed forces outward on the preform which, consequently, flows to adapt to the inner surface of the mold 40A, 40B for set the pressure vessel 41A. It should be noted that, in the example, the regions of the axial opening of the preform flow to adapt to the threads of the inserts 43, 45.

The heat application is then interrupted, and once the mold 40A, 40B and the pressure vessel formed 41A they have cooled sufficiently, the mold is opened, they are unscrewed the threaded inserts 43, 45 and the bag of silicone rubber 42 and heater 48, leaving the container to pressure formed. It will be noted that, as depicted in 51, the internal threads have been formed, as provided in the example, in the axial openings of the composite container a pressure formed.

In the preparation of some containers pressure compounds, such as domestic water heaters, The color of the finished product may be important. Is by possible assumption to prepare a preform according to any of the processes described above, using one or more materials They are already colored. However, there are two objections potential to this approach, that is to say that the raw materials Pre-colored are more expensive and have a number of limited colors. However, using the principles of In the present invention, a pressure vessel can be colored finished, differently and highly satisfactory.

Similarly, there are applications of pressure vessels, such as for water storage ultrapure, gas storage (e.g. propane, butane, gas natural, etc.) and food, where it is desirable to have a liner entirely waterproof inside inside a container composed of Pressure. A process can also be developed according to the invention to obtain said inner lining entirely waterproof. An example, shown in fig. 17-20,  indicates how to provide the desired exterior color to a compound pressure vessel, as well as an inner liner completely waterproof. Obviously you can get any of the features individually.

Therefore, with reference to fig. 17, be introduces into a two-piece mold 60A, 60B a set that includes a preform 63 (manufactured according to any of the methods described above), surrounded by a sheet 67 of material thermoplastic of the desired product color. If you are going to apply a inner lining entirely waterproof, a sheet is introduced thermoplastic 66 with the desired characteristics inside preform 63 before juxtaposing the pieces properly inserted 64, 65. The mold 60A, 60B includes sections lowered faces 61A, 61B and 62A, 62B which, when the mold is closed, provide steps into the mold.

With reference now to figure 18, the mold 60A, 60B is closed, and the inside of the mold is coupled to a vacuum source 68, through conduit 69. Alternatively or additionally, the inside of the inner lining 66 (or the inside of the preform 63 if no internal lining is to be incorporated) it couples to a source 70 of pressurized gas through a conduit 71. As shown in fig. 19, heat Q is applied to the mold with the so that all components of the composite container a pressure to be formed to convert to the fluid state, while the inside of the mold is evacuated as indicated by arrows 72 and the inside of the inner lining 66 (or of the preform 63 if there is no inner lining) is subjected to pressure as indicated by arrows 73. By  consequently, the three (or two) components are consolidated and the outer surface of the color sheet 67 adapts to the shape inside the mold 60A, 60B. Once it has been allowed to cool the mold (or has cooled down) and has opened, the resulting pressure compound vessel 74, shown in the Figure 20 (as a cross-sectional sheet) is ready to any other further processing. As indicated previously, inserts 64, 65 can of course be threaded for further disposal, leaving one or two openings axial, as appropriate, for the intended purpose of the pressure compound vessel.

In figs. 21-23, a Similar process for manufacturing a pressure vessel. The fig. 21 shows a two-piece mold 80A, 80B that can be, e.g. eg, a single-sheet metal mold, so that they can be simultaneously form a certain number of pressure vessels. He mold, shown located in a suitable oven 81, has been loaded with a preform 82, manufactured according to any of the methods and with any of the materials and / or combinations of materials described above, and has at least one opening to access inside. A base bag is introduced of a thermoplastic sheet 82, which is intended to function as a liner whole in the finished pressure vessel, inside the preform 82 before closing the mold 80A, 80B.

With reference now to fig. 22, is transmitted heat Q from oven 81 to mold 80A, 80B, gas is applied to pressure P (from a suitable source, not shown) into the thermoplastic sheet bag 83, orienting it towards the inner surface of preform 82. In addition, vacuum V is generated (from any suitable source not shown) inside the mold 80A, 80B and therefore externally to preform 82. This state is maintained until the plastic materials of the preform 82 and the plastic foil bag consolidate and the outer surface of the composite structure takes the form of inside of the mold. Then, the mold is taken out of the oven 81, left cool and open to remove the pressure compound vessel finished 85, shown in figure 23, constituted by the full structure, which includes the 82A molded preform and the liner of plastic sheet 83A, which has melted inside the pressure compound vessel.

Compound pressure vessels, manufactured according to all the processes described above, they have remarkably improved performance and aesthetic characteristics with respect to those that are manufactured with the processes of the state of The technique. More particularly, they can withstand pressures and higher temperatures, are more impact resistant and show  a remarkably improved finish. They also have good machinability characteristics and therefore can be welded easily cut, drill, thread, stamp or subject to similar operations as desired, to obtain a product High quality finish.

Therefore, although the principles of invention have been clearly stated in the embodiments illustrated, subject matter experts will realize that they can make many modifications to the structure and the components used in the practice of the invention, particularly adapted to specific environments and requirements of work, without departing from the scope of these principles.

Claims (9)

1. Process for manufacturing a container compound comprising the following stages:

TO)

preforming a sheet structure compound (7) for the container, sheet structure manufactured by at least partly from a thermoplastic material and that has a thermoplastic laminar liner (1) that seals the inner surface of the same;

B)

in a mold (13), heat the composite sheet structure (7) and the liner thermoplastic sheet (1), while applying at least one force, which tends to push the thermoplastic sheet liner and the composite laminar structure outwards;

C)

continue with stage B) until the thermoplastic laminar lining and the composite laminar structure is consolidate and the outer surface of the laminar structure compound become fluid and flow to adapt to the surface inside the mold, thus forming a container compound;

D)

leave cool the formed composite container; Y

AND)

take from the mold the composite container formed.

2. Process according to claim 1, wherein the aforementioned stage A) comprises the preforming of a structure thermoplastic composite sheet (7) for the container based on fiber (6) and a thermoplastic material, composite sheet structure thermoplastic comprising the thermoplastic laminar liner (1) which seals the inside of the surface of it. 3. Process according to claim 1, wherein the aforementioned stage A) comprises the preforming of a structure composite thermoplastic sheet (7) for the container, rolling fiber (6) and a thermoplastic material on a mandrel thermoplastic, composite thermoplastic laminar structure that comprises said thermoplastic sheet liner (1) that seals the inner surface of it. 4. The process of any of the claims 1 to 3, wherein, during steps C) and D), the force (at least one) is obtained at least in part evacuating the mold (13). 5. The process of any of the claims 1 to 3, wherein, during steps C) and D), the force (at least one) is obtained at least in part pressing the thermoplastic laminar lining (1). 6. The process of any of the claims 1 to 3, wherein, during steps C) and D), get forces that tend to push the plastic sheet liner against the inner surface of the thermoplastic sheet structure  composed by means of simultaneous evacuation of the mold (13) and applying pressure inside the thermoplastic laminar lining (one). 7. The process of any of the claims 1 to 6, wherein the sheet liner material thermoplastic (1) is chosen within the group consisting of polyethylene, polypropylene, polybutylene, terephthalate and polyethylene Terephthalate 8. The process of any of the claims 1 to 7, wherein the thermoplastic material in said composite sheet structure (7) is chosen within the group formed by polyethylene, polypropylene, polybutylene, terephthalate and polyethylene terephthalate. 9. The process of any of the claims 1 to 8, wherein step C) includes the heating of the mold.